Sealed electrical cable duct and method for production thereof

ABSTRACT

A housing with electronics arranged therein includes a wall defining a penetration therethrough. A flexible conductor support made of plastic and including electrical conductors embedded therein extends through the penetration opening for electrical connection of at least one of the conductors to the electronics in the housing. The plastic of the flexible conductor provides insulation of the electrical conductors. The conductor support is sealed and mechanically fixed by a conductor support seal arranged between the penetration opening of the housing and the conductor support, the conductor support seal being molded directly onto the flexible conductor support and the housing.

PRIORITY CLAIM

This is a U.S. national stage of application No. PCT/EP01/10748, filedon Sep. 17, 2001. Priority is claimed on that application and on thefollowing application:

County: Europe, Application No.: 00120778.6, Filed: Sep. 22, 2000.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a sealed electrical cable penetration and amethod for production thereof.

2. Description of the Prior Art

In motor vehicles, it is increasingly required that control electronics,accommodated in a housing, such as, for example, gear motor drives forwindow lifts, sunroofs, or the like, be integrated with and connected tothe engine and/or transmission, the control electronics mounted on acircuit carrier that is required to be shielded from the oils used inengines and transmissions, as these oils contain chemically extremelyaggressive additives. At the same time,however, electrical conductorsmust penetrate the shielding to allow engine or transmission componentsto be controlled or supplied via the control electronics.

A connector system that is suitable for use in such conditions is knownfrom European patent EP 0 513 263 B1. Here, a flexible film withelectrical traces is led through between a closure support and a housingand establishes an electrical connection between a component inside thehousing and a component outside the housing. To accomplish sealingbetween the flexible film and the closure part or the housing, theflexible film must be surrounded by a seal. The sealing of the closurepart with respect to the housing and the film is relatively complex orcannot be safely guaranteed in all cases.

To simplify the manufacturing and assembly process, DE 197 42 178 C1discloses how the conductor support can be introduced directly into thehousing wall through which the traces are to be routed. However, thiscan cause problems due to excessively high thermal loading of thesubstrate material. Some of these problems can sometimes be circumventedby selecting an appropriately heat-resistant, but more cost-intensivematerial such as polyamide.

SUMMARY OF THE PRESENT INVENTION

This object can be achieved by a device for sealing an electrical cablepenetration through the wall of a housing, wherein the housing has awall defining a penetration opening therethrough, the device including aflexible conductor support made of plastic and including electricalconductors embedded therein, the plastic providing insulation of saidelectrical conductor. The flexible conductor support is inserted throughthe penetration opening and sealed and mechanically fixed therein by aconductor support seal. The conductor support seal is made from plasticand molded directly onto the flexible conductor support and the housing.

For the manufacture of the cable penetration according to the invention,the mass temperature of the sealing material can be kept lower than thatof the previously injection-moldable housing and therefore aninexpensive material with lower temperature resistance, in particular athermoplastic, can be selected. Furthermore, a high degree ofleak-proofness between an opening-side housing edge and a housing coverto be placed thereupon can be ensured, as the interposed sealing layerexhibits a high degree of homogeneity over its entire sealing surfacearea because of the absence of the conductors encapsulated in their ownseparate penetration opening. The possibility of molding the conductorsupport and the seal or sealing layer in and on respectively in a singleoperation as well as the possibility of injection-molding thedimensionally complicated housing without simultaneously molding in theconductor support results in a significant and, particularly forautomated production of a mass-produced article, advantageous reductionin manufacturing costs.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective view of a pot-shaped electronics housing havinga conductor support extending from its upward facing base area through apenetration opening and forming a seal;

FIG. 2 is a perspective view of the pot-shaped electronics housingaccording to FIG. 1 with upward facing pot edge side with sealing layerfor sealing with respect to a housing cover to be placed onto theleakproof closure;

FIG. 3 is a plan view of the electronics housing according to FIGS. 1and 2;

FIG. 4 is a sectional view of the electronics housing along intersectionIV—IV in FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 to 4 show a pot-shaped injection-molded polyamide plastichousing 1 for accommodating control electronics mounted on a partiallyindicated circuit board 5 fixed inside the housing 1. Connectedmonolithically to the housing 1 is a brush supporting arrangement 4 withbrushes 4.1 and 4.2 disposed therein, into the interior of which thecircuit board 5 partially extends. In a manner known from U.S. Pat. No.5,528,093, the entire contents of which are incorporated herein byreference, the brush supporting arrangement is disposed between, on theone hand, the front faces of a motor housing of a commutator motor and,on the other, a transmission housing of a worm transmission such that,in the area of the commutator, the brush supporting arrangement 4 may beexternally enclosed by the motor housing and transmission housing. Thehousing 1 accommodating the control electronic can be tightly sealed bya transmission-side housing cover 6 which can be placed on the top edgeof the housing. For leakproof sealing of the overlying components, thereis provided a monolithic sealing layer 2.2 of a seal 2, the sealinglayer 2.2 being molded onto the housing on the edge side.

For making contact between the control electronics of the circuit board5 accommodated in the cavity of the housing 1 on the one hand and anexternal supply connection on the other, conductors 3.1 embedded in aflexible conductor support 3 are used. The conductor 3.1 can beconnected to the circuit board 5 using contact points angled towards thecontact plane of the circuit board 5 inside the housing and which leade.g. to a customer-side plug connection (not shown here) using contactpoints outside the housing.

A separate penetration opening 1.1 provided outside the area or theseating layer 2.2 in the base area of the pot-shaped housing 1 and of ahousing side wall in proximity thereto is used for sealed electricalrouting of the conductors 3.1 from the inside of the housing 1 to theoutside. The flexible conductor support 3 containing the conductors 3.1embedded therein as a kind of foil conductor is molded in thepenetration opening 1.1 with a conductor support seal 2.1 made of athermoplastic or similar material.

According to one embodiment of the invention, the conductor support 3containing the embedded, specifically molded-in conductors 3.1 is keptrouted inside the housing 1 along the housing side wall near thepenetration opening 1.1 by a seal extension 2.3 by molding it on as faras its offsettable contact-making end with the circuit board 5. Theconductor support seal 2.1 and the edge-side sealing layer 2.2 as wellas, if necessary, the seal extension 2.3 are preferably injection-moldedas a one-piece seal 2 in a single operation.

An advantageous method for manufacturing the cable penetration accordingto the invention is characterized by the following operations:

Fabricating, in particular injection-molding, the housing with theseparate penetration opening provided for the conductor supportlead-through and possibly the housing opening that can be closed bymeans of the housing cover by interposing a sealing layer;

Inserting the conductor support through the penetration opening of thehousing;

Injection molding the conductor support seal around the conductors andonto the housing in the area of the housing edge of the penetrationopening and the sealing layer onto the housing in the area of itshousing edge provided for placement of the housing cover.

To summarize: To reduce the material and production costs for a sealedelectrical cable penetration through the wall of a housing 1, electricalconductors 3.1 are embedded in a flexible conductor support 3 made ofpolyester; the conductor support 3 is molded in place by injectionmolding of a conductor support seal 2 made of a thermoplastic materialin a separate penetration opening 1.1 in the wall of the housing 1 madeof a polyamide.

What is claimed is:
 1. A device for sealing an electric cablepenetration through the wall of a housing, comprising: a housingincluding electronics arranged therein and having a wall defining apenetration opening therethrough; a flexible conductor support made ofplastic and including electrical conductors embedded therein, theplastic providing insulation of said electrical conductors, wherein saidflexible conductor support extends through said penetration opening forelectrical connection of at least one of said electrical conductors tosaid electronics in said housing; and a conductor support seal providingleakproof sealing and mechanical fixing between said penetration openingdefined by said housing and said flexible conductor support, saidconductor support seal being made from plastic and molded directly ontosaid flexible conductor support and said housing.
 2. The device of claim1, wherein said conductor support seal is molded around the conductorsin said flexible conductor support and onto edges of said housingdefining said penetration opening.
 3. The device of claim 2, furthercomprising a housing cover covering said housing and a sealing layerinterposed between said housing cover and said housing for providing ascaled connection between said housing cover and said housing, whereinsaid penetration opening is located outside of an area of said sealinglayer.
 4. The device of claim 3, further comprising a seal extensionmolded together with said conductor support seal, wherein said conductorsupport is held in a fixed position in said housing outside of saidpenetration opening by said seal extension.
 5. The device of claim 4,wherein said seal extension, said conductor support seal and saidsealing layer are molded together as one integral piece.
 6. The deviceof claim 3, wherein said conductor support seal and said sealing layerare molded together as one integral piece.
 7. The device of claim 2,further comprising a seal extension molded together with said conductorsupport seal, wherein said conductor support is held in a fixed positionin said housing outside of said penetration opening by said sealextension.
 8. The device of claim 7, wherein said seal extension andsaid conductor support seal are molded together as one integral piece.9. The device of claim 1, further comprising a seal extension moldedtogether with said conductor support seal, wherein said conductorsupport is held in a fixed position in said housing outside of saidpenetration opening by said seal extension.
 10. The device of claim 9,wherein said seal extension and said conductor support seal are moldedtogether as one integral piece.
 11. The device of claim 1, furthercomprising a housing cover covering said housing and a sealing layerinterposed between said housing cover and said housing for providing asealed connection between said housing cover and said housing, whereinsaid penetration opening is located outside of an area of said sealinglayer.